This invention relates to area meters.
In the one class of area measuring device, the object to be measured and a sensor are moved with respect to each other, with the sensor generating pulses proportional to the area of the object that is being measured. A counter counts the pulses and indicates the area. Certain types of this class of area measuring device include a conveyor transport system that moves the object past the scanner.
In a prior art type of area measuring device of this class, the object to be measured is scanned by a light beam which sweeps across the object and the light not bocked by the object is collected by a photocell. During the time of each scan that light is blocked by the object, pulses are counted. The pulses are generated in a photocell by light which passes through apertures in a disc, driven by gears in synchronism with the conveyor belt. The pulses are counted to indicate the area.
The prior art apparatuses have the disadvantage of being designed to measure objects of substantially the same width and thus losing resolution for smaller objects and tending to be inaccurate in measuring edges.